Method for making resin dental plates and flasks

A flask comprising:

• a splittable flask body which comprises an upper lid member, a tray member and a lower lid member, all formed of a material through which microwaves are transmittable,
• an injection attachment mounted on a mounting port formed of axially aligned cut-out portions of said tray member and said lower lid member and having an axial resin injection hole, and a sprue-opening closure member for closing said resin injection hole in said injection attachment,
• a cylinder filled with a pasted resin and a plunger positioned in said cylinder for injecting said resin into said resin injection hole, said cylinder having an end wall with an outlet hole formed therein and a recessed portion formed on a side of said wall opposite said plunger;
• and
• said flask body being provided in the vicinity of a side edge thereof with at least two through-holes and tightening means inserted into said through holes, wherein said tightening means comprises securing members, each formed of a material through which microwaves are transmittable, and wherein said injection attachment is provided with a resin injection hole and with inner and outer stopper members formed of a material through which microwaves are transmittable in such opposite relation as to hold therebetween a wall region of the side of said flask body, said outer stopper member being positioned in said recessed portion formed at said one end of said cylinder.